Process of producing sheet glass



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L. c. MAMBOURG 2?@26938 PROCESS OF' PRODUCING SHEET GLASS Filed July 15,1952 Patented Dec. 31, 1935 UNITED STATES PATENT GFFICE PROCESS GFPRODUCING SHEET GLASS Application July 15, 1932, Serial No. 622,709

3 Claims.

The present invention relates to an improved process of forming sheetglass.

This invention is of particular utility when incorporated in a rollingmachine for producing continuous sheet glass wherein a pair ofhorizontally arranged forming rolls are positioned above a workingreceptacle containing a mass of molten glass, said rolls being arrangedrela-- tive to one another to create a vertical sheet forming passtherebetween and being positively driven in a manner to draw arelatively heavy body of glass upwardly from the molten mass and reduceit to a sheet of substantially predeternnned and uniform thickness. Thesheet, after being formed, is preferably drawn upwardly for a relativelyshort distance and then deflected into the horizontal plane about arotatable bending roll. With the above type of rolling machine, one ofthe forming rolls is ordinarily mounted in a xed position while theother roll is movable toward and away from the fixed roll.

Heretoiore, it has been customary to urge the movable forming rolltoward the fixed forming roll by means of a counterweight, and toprovide an adjustable stop member for limiting the movement oi saidrolls toward one another. Furthermore, it has also been the usualpractice to provide sufficient weight to maintain the movable roll atall times against the stop member except upon the passage of foreignmatter or clay stones between the rolls, at which time the movable rollwould be permitted to temporarily move away from the roll. In otherwords, the pressure exerted by t -e counterweight to hold the movableroll against the stop member was such that during the normal rollingoperation, the movable roll would be held in a iiXed position and onlyunder unusual circumstances, such as to permit the passage of claystones or the like therebetween, would this roll be moved away from theiixed roll. Thus, the distance between the iixed and movable rollsdetermined the thickness of sheet produced. That is to say, thethickness of sheet produced was equal to the width of the pass betweenthe forming rolls which was controlled by adjustment of the stop member.I have found, however, that when sufcient weight is provided to maintainthe movable roll always against the stop member as explained above, arolling pressure greater than that required to roll the glass to sheetform is had, and that this excessive rolling pressure tends to cause astagnation and devitrication of the glass below the forming rollsresulting in the formation of socalled darts or streaks in the sheet.These darts are nothing more or less than devitried glass which is drawnupwardly into the sheet.

The principal aim and object of this invention is to obviate thetendency of the glass to become stagnant beneath the forming rolls andthereby do away with the formation of darts or streaks in the sheetresulting in the production of glass of an improved quality.

Briefly stated, according to the present invention, the stop memberreferred to hereinabove for limiting the movement of the movable formingroll toward the fixed forming roll is eliminated and the said movableroll permitted to iicat toward and away from the said fixed roll so thatthe thickness of sheet produced will be governed by the weight of thecounterweight and the viscosity of the glass being rolled. In otherwords, only sufficient pressure is exerted upon the glass being rolledto produce a sheet of the desired thickness so that no excessive rollingpressure is had. Consequently, the thickness of sheet produced iscontrolled by varying the pressure of the movable roll upon the glassbeing rolled.

Other objects and advantages of the invention will become more apparentduring the course of the following description when taken in connectionwith the accompanying drawing.

In the drawing forming a part of this application and wherein likenumerals are employed to designate like parts throughout the same,

Fig. l is a vertical longitudinal section through one type of sheetglass rolling apparatus with which the present invention may beincorporated,

Fig. 2 is a side elevation, partially in section, of the supportingmeans provided for each end oi the forming and bending rolls, and

Fig. 3 is a plan View of the counterweight.

Referring now to. the drawing, and particularly to Fig. l, the numeral 5designates a rela-tively shallow working receptacle or pot containing amass of molten glass 6 supplied thereto from any suitable type of glassmelting furnace l. The working receptacle 5 is ordinarily supported uponstools 8 arranged within a heating chamber 9.

Positioned above the working receptacle and extending transverselythereof is a pair of horizontal sheet forming rolls le and il arrangedrelative to one another to create a vertical sheet forming passtherebetween. The forming rolls are adapted to be positively driven inany desired manner so that upon rotation thereof, the said rolls willfunction to draw a relatively heavy body of glass l2 upwardly from themolten mass 6 and reduce the same to a sheet I3 of substantiallypredetermined and uniform thickness. As herein shown, the glass sheet i3is continued upwardly forl a relatively short distance beyond theforming rollslll and il and is then deflected about a rotatable memberor roll I4 into a substantially horizontal plane wherein it is supportedand carried along upon a series of horizontally arranged conveyor rollsI5 into an annealing leer (not shown).

The means herein provided for adjustably supporting the forming rolls l0and li and bending roll ld is illustrated in Fig. 2, and to this endthere is mounted longitudinally above the working receptacle 5, adjacenteach side thereof, a pair of spaced horizontal supporting beams I6, oneonly being shown. Arranged inwardly of adjacent beams i3 are slides Ilon which is adapted to slide a casting i8. Each casting is provided withtransverse openings I9 and through each of these openings passes a bolt20, said bolts connecting the adjacent beams I6 together and preventingseparation thereof. The openings i9 are elongated so that the casting I8can be moved longitudinally of the machine within certain limitsdepending upon the length of said openings.

Each casting I8 carries a vertical sleeve member 2| through whichextends a bolt 22, said bolt having a threaded upper end 23 workingthrough a worm wheel 24 with which meshes a worm 25 carried upon a shaft23. Upon rotation of shaft 23, rotation will be imparted to the worm 25and worm wheel 24, thereby raising or lowering the bolt 22 dependingupon the direction of rotation of the said shaft.

Each supporting bolt 22 carries a depending casting 2l by means of across pin 28 extending through the bolt and also through apertured earson said casting. Two additional members 29 and 33 arey also carried bythe bolt 22, the casting 2l an-d members 29 and 33 being tied togetherby means of bolts 3l. These three parts 21, 29 and 3G constitutesupports for the forming roll IE and bending roll l.

The forming roll lil is preferably maintained stationary during therolling operation although it is of course rotatable about its axis andmay be adjusted vertically with respect to the mass of molten glass fromwhich the sheet is produced. The forming roll il, however, is mounted insuch a manner that it is freely movable toward and away from roll It.The mounting for the roll 'il includes a link 32 pivotally connected bya pin 33 between the ends 34 of the bracket or part 30. The link 32 islikewise pivoted as at 36 to a support 35 for the roll Il. A second link37 is pivotally connected at 38 to the ends 3@ of bracket 3E) and isalso pivoted intermediate its ends to the roll support 35 by a pin 39.

A bell crank lever 40 pivoted intermediate its ends as at 4i to thecasting i8 is connected to the upper end of link 3l by a connecting link.22 pivoted at one end to the bell crank as at i3 and at its oppositeend to said link 37 as at lili. A connector arm l5 is pivotallyassociated with the bell crank as at i6 and is also pvotally connectedto a beam il at 48. The beam il is pivotally supported as at 33 on thecross beam 5S, while the opposite end of the beam carries a plurality ofweights 5l. These weights are preferably in the form of metal discsremovably mounted upon a cross pin 52 and held in place by nuts 53.

With the type of linkage above described and when the various parts arearranged in the position illustrated in Fig. 2, it will be seen that thediscs 5| constitute a counterweight which acts to Vurge the movableforming roll l l toward the fixed forming roll I0. As pointed outhereinabove, it

has heretofore been customary to provide an adjustable stop member tolimit the inward movement of roll Il toward roll l0 and thereby controlthe space between the said rolls and consequently the width of the sheetforming pass. Moreover, the pressure exerted upon the roll Ii Was suchas to maintain the said roll against the stop member during the normalrolling operation so that the sheet produced was of a thickness equal tothe width of the forming pass. The disadvantages incident to the use ofsuch a stop member have also been fully set 'forth above.

According to the present invention, therefore, this stop member has beeneliminated, with the result that the roll l l is permitted to floattoward and away from roll l0. In other words, Vno means is provided tolimit or restrict the movement of roll l! toward roll I3. With such anarrangement, the thickness of sheet produced will be governed by theweight of the counterweight and the viscosity of the glass being rolled.Thus, only sufficient pressure is exerted upon the glass heing rolled toproduce a sheet of the desired thickness so that no excessive rollingpressure is had. That is to say, the rolls will not be caused to assumea denite relation to each other, and in this way the rolling pressurewill not be sufficient to cause a stagnation of the glass below therolls and the disadvantages incident thereto. The thickness of sheetproduced is controlled by varying the pressure of the movable roll uponthe glass being rolled, and this pressure can be varied by increasing ordecreasing the number of weights 5l.

It is to be understood that the form of the invention herewith shown anddescribed is to be taken as the preferred embodiment of the same, andthat various changes in the shape, size and arrangement of parts may beresorted to without departing from the spirit of the invention or thescope of the subjoined claims.

I claim:

1. In the manufacture of sheet glass wherein a relatively heavy body ofmolten glass is passed between a pair of revolving rolls and reducedthereby to a sheet of substantially predetermined thickness, the step ofcontrolling the thickness sheet of substantially predeterminedthickness, in

arranging one of said rolls so that it is freely movable toward and awayfrom the other roll, and in controlling the thickness of the sheetproduced by causing said rolls to exert a pressure upon the glasssufficient only to form a sheet of the desired thickness.

3. The process of producing sheet glass, which consists in passing arelatively heavy body of molten glass between a pair of revolving rcllswhich serve to reduce the same to a sheet of substantially predeterminedthickness, in arranging one of said rolls so that it is freely movabletoward and away from the other roll, and in controlling the thickness ofthe sheet produced by varying the pressure of the movable roll upon theglass being rolled.

. LUKE C. MAMBOURG.

